Ester-amide-acid compounds



3,037,051 ESTER-AMIDE-ACED CQWGUNDS Verner L. Stromberg, Shrewsbury, M0,, assignor to Petrolite Corporation, Wilmington, Del., a corporation of Delaware No Drawing. Filed Aug. 1, 1958, Ser. No. 752,431 14 Claims. (Cl. 260485) This invention relates to the reaction product of two moles of an alkenyl succinic acid or an anhydride thereof (also referred to as ASAA) and one mole of an 3,837,951 Patented May 29, 1962 with other groups, for example aromatic groups, for example phenyl, tolyl, etc. In such instances the alkylene radical need not have three carbon atoms but may have only two, for example it may be ethylene wherein the ethylene radical also contains an aromatic group such as a phenyl group, etc. The amino or alcohol group can be attached to the carbon atoms of the alkylene radical amino alkanol or substituted aminoalkanol having at wherein Z is an alkylene or substituted alkylene radical having at least three carbon atoms, for example from 3 to 12 or more carbon atoms, but preferably 3 to 8 carbon atoms; wherein one each of the R or R on each succinic moiety is an alkenyl radical having at least 2 carbons, for example 2 to 32 or more carbons, but preferably 8 to 18 carbons and the other R or R on each succinic moiety is hydrogen; and wherein Y is hydrogen or a hydrocarbon group, for example an aliphatic group preferably lower alkyl.

This invention also relates to the use of these compositions in various arts, particularly as corrosion inhibitors, such as for oil wells, oil refineries, in slushing oils, refined mineral oil such as gasoline, jet fuel, etc., as leaded gasoline anti-fouling additives, etc.

The aminoalkanols employed in preparing the product of this invention contain alkylene or substituted alkylene radicals having at least three carbon atoms and both an amino and an hydroxyl radical. These can be expressed by the formula:

GH -('JH doubly branched,

CH5 CH3 CH-CH- or multi-branched CH CH --CHz( 1HCH-CH2 etc. In addition, the alkylene groups can be substituted which are primary, secondary, or tertiary carbons. The carbons to which these radicals are attached need not be of the same type. For example, in isopropyl amine,

the preferred aminoalkanol, the alcohol radical is attached to a secondary carbon atom while the amino group is attached to a primary carbon atom. Examples illustrating various positions of attachment of the functional groups are:

5-amino-4-ootanol,

l-amino-Z-hexanol,

2-arnino-3-hexanol, 2-amino-2-methyl-3-hexano1, 3-amino-4-hexanol,

2-amino-l-hexanol, 3-amino-2-hexanol, l-amino-Z-heptanol, 2-amino-3-heptanol, 3-arnino-4-heptanol, l-amino-Z-octanol, Z-amino-S-octanol, 2-amino-2-methyl, 3-octanol, 3-amino-4-octanol, Z-amino-l-octanol, 3-amino-2-octanol, etc.

Although the above aminoalkanols are illustrated with aminoalkanol containing primary amino groups, it should be understood that corresponding compounds containing amidifiable secondary amino groups can also be employed.

Thus, aminoalkanols corresponding to those mentioned herein except that they contain N-aliphatic groups, such as N-alkyl groups, for example methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl, octadecyl, cycloaliphatic, etc., isomeric alkyl groups, etc., can be employed in this invention. In addition, N-alkenyl or N-alkinyl groups can also be employed.

One convenient method of preparing these aminoalkanols is to react ammonia or a primary amine with an alkylene oxide on another hydrocarbon oxide having at least 3 carbon atoms, for example propylene oxide, butylene oxide, octylene oxide, styrene oxide, etc. Other methods of preparing these aminoalkanols are so well known to the art that it is unnecessary to repeat them here.

Any alkenyl succinic acid anhydride or the corresponding acid is utilizable for the production of the reaction products of the present invention. The general structural formulae of these compounds are:

Anhydride H R-CH-C 3 wherein R is an alkenyl radical. The alkenyl radical can be straight-chain or branched-chain; and it can be saturated at the point of unsaturation by the addition of a substance which adds to olefinic double bonds, such as hydrogen, sulfur, bromine, chlorine, or iodine. It is obvious, of course, that there must be at least two carbon atoms in the alkenyl radical, but there is no real upper limit to the number of carbon atoms therein. However, it is preferred to use an alkenyl succinic acid anhydride reactant having between about 8 and about 18 carbon atoms per alkenyl radical. In order to produce the reaction products of this invention, however, an alkenyl succinic acid anhydride 101 the corresponding acid must be used. Succinic acid anhydride and succinic acid are not utilizable herein. For example, the reaction product produced by reacting with succinic acid anhydride is unsatisfactory. Although their use is less desirable, the alkenyl succinic acids also react, in accordance with this invention, to produce satisfactory reaction products. It has been found, however, that their use necessitates the removal of water formed during the reaction and also often causes undesirable side reactions to occur to some extent. Nevertheless, the alkenyl succinic acid anhydrides and the alkenyl succinic acids are interchangeable for the purposes of the present invention. Accordingly, when the term alkenyl succinic acid anhydride, is used herein, it must be clearly understood that it embraces the alkenyl succinic acids as well as their anhydrides, and the derivatives thereof in which the olefinic double bond has been saturated as set forth hereinbefore. Non limiting examples of the alkenyl succinic acid anhydride reactant are ethenyl succinic acid anhydrides; ethenyl succinic acid; ethyl succinic acid anhydride; propenyl succinic acid anhydride; sulfurized propenyl succinic acid anhydride; butenyl succinic acid; 2-rnet'hyl-butenyl succinic acid anhydride; 1,2- dichloropentyl succinic acid anhydride; hexenyl succinic acid anhydride; hexyl succinic acid; sulfuri'zed B-methylpentenyl succinic acid anhydride; 2,3-dimethylbutenyl succinic acid anhydride; 3,3-dimethylbutenyl succinic acid; '1,Z-dibromo-Z-ethylbutyl succinic acid; heptenyl succinic acid anhydride; 1,2-diiodooctyl succinic acid; :octenyl succinic acid anhydride; Z-methylheptenyl succinic acid anhydride; 4 ethylhexenyl succinic acid; 2-isopropylpentenylsuccinic acid anhydride; nonenyl succinic acid anhydride; 2-propylhexenyl succinic acid anhydride; decenyl succinic acid; decenyl succinic acid anhydride; 5-methyl-2-isopropylhexenyl succinic acid anhydride; 1,2-dibro-mo-2-ethylootenyl succinic acid anhydride; decyl succinic acid anhydride; undecenyl succinic acid anhydride; 1, 2-dichl'oro-undecyl succinic acid; 3-ethyl 2-t-butylpentenyl succinic acid anhydride; dodecenyl succinic acid anhydride; dodecenyl succinic acid; Z-propylnonenyl succinic acid anhydride; 3 butyloctenyl succinic acid anhydride; tridecenyl succinic :acid anhydride; tetradecenyl succinic acid, anhydride; heXadecenyl succinic acid anhydride; sulfuriz ed octadecenyl succinic acid; octadecyl succinic acid anhydride; 1,Z-dibromo-Zanethylpentadecenyl succinic acid anhydride; 8-propylpentadecyl succinic acid anhydride; eicosenyl succinic acid anhydride; 1,2-dichloro-2-methylnonadecenyl succinic acid anhydride; 2-octyldodecenyl suctures, as well as relatively pure anhydrides, are utilizable herein.

In general, the alkenyl succinic acid anhydride is reacted with the aminoalkanol in a proportion of 2 moles of alkenyl succinic acid anhydride for each mole of aminoalkanol. Of course, more than 2 moles of alkenyl succinic acid per mole of aminoalkanol can be employed, leaving an excess of alkenyl succinic anhydride in the reaction mixture.

'For example, when two moles of an alkenyl succinic acid are reacted with one mole of an aminoalkanol or two moles of an alkenyl succinic acid anhydride are reacted with one mole of an aminoalkanol, a reaction product is produced, representing the complete chemical interaction of the reactants. However, when three moles of an alkenyl succinic acid anhydride reactant are reacted with the aminoalkanol, a product is produced which comprises a physical mixture of the reaction product plus the unreacted alkenyl succinic anhydride.

The reaction between the alkenyl succinic acid anhydride and the aminoalkanol takes place at any temperature ranging from ambient temperatures and upwards. This reaction results in an amide-ester formation reaction effected by the well known reaction of the anhydride group with an amino and an alcohol group. This reaction proceeds at any temperature, but temperatures of above 100 C. are preferred. Thus, the reaction can take place at 20 to 200 C., but preferably 100 to 150 C.

The reaction between the alkenyl succinic acid anhydride reactant and the aminoalkanol proceeds smoothly in the absence of solvents. However, the occurrence of undesirable side reactions is minimized when a solvent is employed and therefore the use of a solvent is preferable. Since a small amount of water might be formed when an alkenyl succinic acid anhydride is used in the reaction, the solvent employed may be one which will form an azeotropic mixture with water.

The time of reaction is dependent on the size of the charge, the reaction temperature selected, and the means employed for removing any water from the reaction mixture. Ordinarily, the addition of the anhydride reactant is substantially complete within a few minutes. The same products can be produced at temperatures below 100 C.

for a reaction time of less than one hour. In order to insure complete reaction, particularly when the alkenyl succinic acid is employed, one may continue heating for several hours. For example when benzene is' used as the solvent at a temperature of 100-110 C., and water is removed, as occurs with alkenyl succinic acid, heating maybe continued for about five hours. When water is formed during the reaction, as when an alkenyl succinic acid is used, the completion of the reaction is indicated by a substantial decrease in the formation of Water. In general, the reaction time will vary between several min- 7 utes and about ten hours.

cinic acid; 1,2-diiodotetracosenyl succinic acid anhydride;

hexacosenyl succinic acid; hexacosenyl succinic acid anhydride; and hentriacontenyl succinic acid anhydride.

The methods of preparing the alkenyl succinic acid anhydrides are well known to those familiar with the art.

'The most feasible method is by the reaction of an olefin with maleic acid anhydride. Since relatively pure'olefins are difficult to obtain, and when thus obtainable, are often mixtures of olefins with maleic acid anhydride. Such mixinbefore, and then the solvent can be added to the reaction product While it is still hot. Dependent on the type of. reaction product involved and of final product desired, the solvent can be used in any amount, thereby producing reaction products containing from about one percent by weight of solvent up to asmuch as 99 percent by weight of solvent.

The reaction which takes place can be expressed by the following equation, wherein the units have the meaning heretofore specified:

6 In general, the compositions of this invention are prepared by adding two moles of ASAA and one mole of the aminoalkanol to about 200 m1. of a suitable solvent E f (xylene is used in the examples), heating to 150 C., R-O-i: Y holding it at this temperature for 5-10 minutes and then (or acid) i; allowing the reaction mixture to spontaneously cool to room temperature. The reaction vessel employed is HC-C H H equlpped with a mechamcal stirrer thermometer and a t t l 13? Ef "T 1 M 1 xamp e wo mo es 0 e apropeny succrmc an- HO O P 9 fr hydride 532 grams) is stirred with 200 m1. of Xylene R R and one mole of isopropanol amine. The reason why the position of the R groups on the succinic moiety are not specifically designated is that two possible reactions can take placeone, Where the R and NH,CH JHOH R groups are adjacent to the amido or ester group, and or V i p a 7 V n V W The other, Where t R groups f l f to the (75 grams) is then added. This mixture is then heated free carboxyhc acrd group. Although it 1s belleved that to reflux at 150 Q, auowed to remain at h temperathe chlef Ramon Product 15 as follows: ture for five minutes, and then allowed to cool spontaneo 0 Y O ously to room temperature. The product is the ester- P l amide-acid product corresponding to the reactants.

In view of the above description and the fact that the preparation of other compositions of this invention are M Q prepared in the same manner, it would be unnecessary H0 C-CHrCH-N-ZO--CCHCHz-CLOH and repetitious to repeat the details of each preparation. Therefore, the compounds are summarized in the followis also iormed. ing Table I.

TABLE I O H d HO(ii-(fH?HC-N-Z-O-C-(FBFCH-C-OH R R R Ex. One of R One of R Y J Z r 1 Allyl Allyl H CHCH- r 2 (in CH3 -CH:-CH- r 3 (in 02H; -CH2-CH- lCHa CH1 4 do .d0 H -CHzCH- (3113 E 5 -do .-do CH3 CH2CH- 6 do .-fl H -GHZ JH 7 an fln CH3 -oH,-c| H- 8. H r)s-- (His 9 Octenyl (straight chain) Octenyl (straight chain) H CHr-GH- 10 (in an CH3 -CH2CH- CH3 1! !1n fin 0 115 -CHz-(EH CTABLE I-Oontinued One of B One of R Octenyl (branched) Decenyl (straight chain) Octenyi (branched) Decenyl (straight chain) TABLE I-Continued Ex. One of B. One of R Y Z 31 d0 "do CH CH7OH s2 .-do d0 H o11,

CH: 33 Tetrapropenyl Tetrapropenyl H CH',-( JH CH: 34 do do CH CH H 35 d0 d0 C 11 -CH H- CH: 3112 CH, CH

CH: 3112 CH 'CH2(|3H- H CH2([3H- 39 --d0 d0 CH3 --CHzCH- 40 do ..d0 H (CH,)3

I 7 CH: 41 Triisobutenyl Triisobutenyl H -CHz( .'IH

CH; 42 do do 0H -CH;(3H

CH: 43 do do 0:115 -CH( JH-- CH: 7112 44 -d0 .do H -CH1(!,H

7 CH3 (EH: 4% do.. CH CHz-( .,H

46 -d0 H CH ('|JH- 47 do .do 0H CH2?H- 48- do d0 H -(CHz)z-- v A CH: 49 Dodecenyl (straight chain) Dodecenyl (straight chain).. H CH2( JH- 50 .60-- do 'OH CH2OH TABLE I-Oontinued Ex, One of R One of R Y Z CH3 51 .do .do 02115 OHa-H CH3 lHz 52 .do -do H -OH 3H- CH: (I311? 53 .do .do 0H -0Hr JH- 54 -do 0 H CHz-(|JH 55 -do .do CH -0H, :H-

CH: 57 Tetradecenyl (straight chain)..- Tetradecenyl (straight chain) H CHz-( 3H-- OH: 55 d0 -do CH -CH;(3H

CH: 7 59 -do onHs CH1-(LJH so -do do H Aim--011- CH3 3H2 s1 -do .do CH -'0H, :H

62 -do -do H om-on e3 -do '-do 0H 43112-015 64 -do -do-.. H (OH)3 CH3 65 Heptadecenyl (straight chain)..- Heptadecenyl(straightchain)..- H -CH1 !2H v 7 'CH: 66 -do -do Q. CH OHQ-(Jlk V 0113 67. .do (V10 CzHu CHq H CH3 3 (IJH? es -do 4&0.- H CH 'H 7 I 10113 a, 1 )112 69 .do .310. 0H !v OH('-)H TABLE I-Continued Ex, One of R One of R Y Z CH; 89 Mixed OH (alkenyl) Mixed C (alkenyl) H CH JH CH; 90 do .do CH; CH2(!7H CH; 91 do do 02H; CH- CH- CH (3H,

92 do ..d0 H CH2CH- OH: I H, 93 -d0 d0 CH CH 3H 94 do .-d0 H -CHz-CH- 95 do do CH; -0H2?H- 96 do "do- H (CH2)3 7 CH: 97 Mixed Ca- (alkenyl) Mixed CHMaIkenyI) H -CHz( )H- CH: 98 do d0 CH; -CH2(!'JH- CH: 99 do d0 02H; -CH-( ?H- 100 do do H CH2OH 2 101 d0 d0 CH CHz( H 102 do do H -CH (|3H* 103 do d0 CH --CH1?H- 104 do ..d0 H (CHa)s CH: 105".-- Mixed C1o-1z(a1keny1) Mixed C1o-1z(alkeny1) H -CH1( JH CH: 106 do do CH -CHq( 3H CH3 107 ..d0 do cgHs -CHr( )H- 108.-.. do do H GH2CH TABLE I-Oontinued Ex. One of R One of R Z 70 do do CH(|3H 71 do do CE1-C3H 72 do do -(CHz)a CH3 73 Octadecenyl (straight chain). Octadecefiyl (straight chain) -CH2( JH A CH8 7 74 do do CHa( ]H CH3 75 do 10 CH2-( 3H CH $152 76 do do; --CH2 CH CH; (111, CH2-C H-- -GHQ-CH- 79 do do CH -CH so do do oH, 3--

CH; 81 Tricosenyl (straight chain) 'ljflcoenyl (si' raight chain) -CH:( H

7 0H: 82 do do CH2( JH- GHQ 83 do do CH2( )H-- CH3 7 V V V 1 2 84 -do do .1 --0H2--( JH- CH; 6H, -oH( JH -OH2 ?H s7 do do n: -on m- A 88 do do V(0H,) V

TABLE IContinued EX. One of B One of R Y Z (IZHa 109 do dn CH -CH2-CH 110 "do"--- rin H -CHg-(|JH 111 ..d0 do CH OHz-CH-- 112 do dn H (CH2)3- r 113- Octenyl (branched) Tetrapropenyl H OH2CH (iiHs 114 d0 d0 CH CHz-CH (IJHz 115 d0 ..d0 C2H5 CHzCH- 11s do do n -CHaCH- 117 do.... do. CH CH:CH

11s do do H CHz-C|lH- 119 d0 do CH CHz-( H- 120 do do H (CH2)a 121 Tetrapropenyl do H OH2-CH2- Unexpectedly, the reaction product produced from aminoalkanol Where Z has less than 3 carbon atoms is unsatisfactory for many uses. Thus, the composition prepared by reacting two moles of tetrapropenyl succinic anhydride and one mole of ethanolamine (Ex. 1211) is unsatisfactory for many of the uses disclosed herein.

1. USE AS AN OIL WELL CORROSION INHIBITOR This phase of the invention relates to the use of the ester-amide-acid compound in preventing the corrosion of metals and particularly iron, steel and ferrous alloys.

More specifically, this phase of the invention relates to the inhibition of corrosion in the petroleum industry with specific reference to producing wells, pipe lines, refineries, tank storage, etc.

The use of a corrosion inhibiting agent in the oil industry and other industries, and particularly for the protection of ferrous metals, is well known. For example, see US. Patents Nos. 2,736,658, dated February 28, 1954, to Pfohl et al., and 2,756,211, dated July 24, 1956, to Jones, and 2,727,003 dated December 13 1955 to Hughes.

More specifically then and particularly from the standpoint of oil production this aspect of the invention relates to inhibiting corrosion caused by corrosive oil well fluids containing for example hydrogen sulfide carbon dioxide, inorganic acids, organic acids, combinations of each with oxygen, and with each other and oxygen. More particularly, it relates to treating oil and gas wells to mitigate metal corrosion and associated difficulties.

It should also be pointed out that the corrosiveness of oil well brines will vary from well to well, and the proportion of corrosion inhibiting agent added to the well fluids should also be varied from well to well. Thus, in some wellsit may be possible to effectively control 'corrosion by the addition of as little as 5 p.p.m. of these compositions to the well fluids, whereas in other wells,

70 it may be necessary to add 200-1,000 p.p.m. or more.

However, these compounds are generally effective in concentrations of 8 to 300 ppm, but preferably 10 to 60 ppm.

For the protection of gas wells and gas-condensate wells, the amount of corrosion inhibitor required will vary del 9 pending upon the amount and type of corrosive agent in the gas and the amount of liquid hydrocarbon and water produced. In general, the amount of the compound required will range from 3 to 50 or more parts but preferably from 5 to parts per million cubic feet of gas produced.

In using these improved compositions for protecting oil Well tubing, casing and other equipment which comes in contact with the corrosive oil-brine production, one finds that excellent results are obtained by injecting an appropriate quantity of a selected composition into a producing well so that it minglcs with the oil-brine mixtures and comes into contact with the casing, tubing, pumps and other producing equipment. One may, for example, introduce the inhibiting composition into the top of the casing, thus causing it to flow down into the well and thence back through the tubing etc. In general, it has been found that this procedure suifices to inhibit corrosion throughout the entire system of production and collection, even including field tank-age.

In case serious emulsion or gel problems are encountered, demulsifiers are advantageously added. This is important not only to avoid the troublesome emulsions and gels themselves, but also to improve corrosion inhibition. The explanation of less efiective corrosion inhibition in the presence of emulsions apparently is that the inhibitor is somewhat surface-active. ,That is, ii is concentrated at interfacial surfaces. Since this surface is great in an emulsion, most of the inhibitor Will be concentrated in these interfaces and littlewill remain in the body of the oil for deposition on the metal surfaces. In many wells, oil-in-Water type emulsions often occur naturally. Insuch wells the inhibitors herein described tending to form water-in-oil type emulsions, .often decrease the emulsion problems naturally present. Thus, in addition to being effective corrosion inhibitors, the herein described products tend to eliminate emulsion problems which sometimes appear when some of the present day inhibitors are used in oil wells or refinery processing.

The method of carrying out this process is relatively simple in principle. The corrosion preventive reagent is dissolved in the liquid corrosive medium 11 small amounts and is thus kept in contact with the metal surface to be protected. Alternatively, the corrosion-inhibitor may be applied first to the metal surface, either as'is, oras a solution in some carrier liquid or paste. Continuous application, as in the corrosive solution, is the preferred method, however.

The present process finds particular utility in the protection of metal equipment of oil and gas wells, especially those containing or producing an acidic constituent such as H 8, CO inorganic or organic-acids and the like;

For the protection of such wells, the reagent, either undiluted or dissolved in a suitable solvent, is fed down the annulus of the well between the casing and producing tubing where it; becomes comingled with thetluid in the 50 well and is pumped or flowed from thewell with these fluids, thus contacting the inner surface of all well-head fittings, conections and flow lines handling the corrosive fluid. V Where the inhibitor; composition is a liquid, it is con-. ventionally fed nto the well annulus by means of a motor driven chemical injector pump, or it maybe dumped periodically (e.-g., once every day or two into the an-' nulus; by means of a so-called boll weevil device or similar arrangement. Where the inhibitor is a solid, it may be dropped into the Well as a solid lump or stick, it may be blownin as a powder with gas, or it may be washed in with a small stream of the well fluids or other liquid. Where there is gas pressure on the casing, it is necessary, of course, to employ any of these treating meth ods through a pressure equalizing chamber equipped to allow introduction of'reagent'intotlie chamber, equaliza tion of pressure between chamber and casing, and travel of. reagent from chamber to well casing.

; Occasionally, oil andgas wells are completed in such a manner that there is no opening between the annulus and the bottom of the tubing or pump. This results, for example, when the tubing is surrounded at some point by a packing held by the casing or earth formation below 5 the casing. In such Wells the reagent may be introduced into the tubing through a pressure equalizing vessel, after stopping the flow of fluids. .After being so treated, the well houl b left closed n f r a P i d. f time su cient to permit the reagent to drop to the bottom of 10' the well.

For injection into the Well annulus, the corrosion inhibitor is usually employed as a solution in a suitable solvent, such as mineral oil, methylethyl ketone, xylene, kerosene, or even water. The selection of solvent will 15 depend much upon the exact reagent being .used and its solubility characteristics. It is also generally desirable to employ a solvent which will yield a solution of low freezing, point, so as to obviate the necessity of heating the solution and injection equipment during winter use.

For treating wells with packed-off tubing, the use of solid fsticks or plugs of inhibitor is especially convenient. These are prepared by blending the inhibitor with a mineral Wax, asphalt or resin in a proportion suffi- -cient to give a moderately hard and high-melting'solid which can be handled and fed into the well conveniently.

These are described in US. Patents 2,559,384. and 2,559,- 385.

These corrosion inhibitors can be used in combination with other well-known corrosioninhibitors, for example,

those containing the cyclic amidine structures, the amido cyclic amidine structures, and the amino cyclic amidine structures, as disclosed in the Blair and Gross Reissue Patent-No. 23,227. When the. herein described products are mixed with corrosion inhibitors of the conventional type in the ratio of one-to-three, one-to-one, three-to-one,

or the like, in numerous instances the elfectiveness of the ---corrosion inhibitor thus obtained. is often significantly greater than the'use of either one alone. 7

The following examples are presented to illustrate the use of the instant compounds as oil well corrosion inhibitors:

Static weight loss tests-These tests are run on both synthetic and naturally occurring fluids. The test pro- ,c e,dure, involvesthe measurement of the corrosive action of the fiuids inhibited by the compositions herein described upon sandblasted S.A.E. 1020 steel coupons measuring /8 x 3% inches under conditions approximating those found in an actual producing well, and the comparison thereof with results obtained by subjecting identical test coupons to the corrosive action of identical fluids containing no inhibitor.

Clean pint bottles are charged with 200 ml. of 10% sodium chloride solution saturated withhydrogen sulfide r' and 200 ml. of mineral spirits and a predetermined amount of inhibitor are then added; In all cases the inhibitor concentrations are "based on the, total volume of fluid. Weighedcoupons are then added, the bottles tightly sealed and allowed to remain at room temperature for 3 days. The coupons are thenremoved, cleaned by immersion in inhibited 10% hydrochloric acid, dried and weighed.

The changes in the weight-of the coupons during the corrosion test taken as'a measurement of the effectiveness of the inhibitor compositions. Protection percent-ages are calculated for each test coupon taken from the inhibited fluids in accordance with the'followingformula:

{Jig- =percent protection i 1 V I 7 tion of oil well fluids.

21 TABLE 11 Use as an Oil Well Corrosion Inhibitor Test Compound Test Compound 2. USE AS A CORROSION INHIBITOR FOR REFINED PETROLEUM it This phase of the invention relates to corrosion inhibited refined petroleum products, and in particular concerns refined petroleum products, oil compositions adapted to protect ferrous and other metal surfaces with which they came in contact from rusting and other types of corrosion. Still more, this phase of the invention relates to a method and composition for inhibiting the rusting characteristics of petroleum distillates.

As is well known, simple films of petroleum products aiford only limited protection to metal surfaces against rusting and other types of corrosion and in general cannot be relied upon to provide sufiicient protection in the presence of moisture or even under conditions of high humidity. This is true, even though the petroleum products are relatively pure and substantially free of the naturally corrosive components present in oil issuing from an oil well which contains natural occurring corrosive agents such as H S, CO inorganic and organic acids, combinations thereof, etc.

One problem which exists in the handling and use of refined petroleum products, such as petroleum distillates, is the rusting which frequently occurs in storage containers such as pipelines, storage tanks, engines, etc. In order to reduce and overcome the problems, many solutions have been suggested. As a matter of fact, a great amount of technical consideration is now being given to the discovcry of effective rust inhibitors for petroleum products. The rusting problem which occurs in storing and using petroleum products occurs usually as the result of traces of moisture which are inevitably present in petroleum distillates. Moisture finds its way into the distillates in a variety of ways. While water is not appreciably soluble in petroleum distillates traces of moisture are, in fact, dissolved in heating oil, gasoline, kerosene, jet fuels, etc. Again, it is impossible to prevent entrainment of moisture in such products during storage and handling. In this connection, for example, storage tanks are generally provided with breather devices to permit the intake and exhaust of air during atmospheric temperature changes. As a result, cool, moisture-laden air is generally drawn into a storage tank at night, resulting in the condensation of moisture in the tank. A portion of this moisture is dissolved in or entrained in petroleum products when pumped from the storage tanks.

I have now discovered that refined petroleum products, for example petroleum distillates, containing minor amounts of our composition, for example at least 5 p.p.m., for example to 200 p.p.m. or more, but preferably 50 to 100 p.p.m. elfectively inhibit the rusting and corrosion of metals, particularly ferrous metals without adversely afiecting the properties of the petroleum products.

The following examples are presented to illustrate the instant compounds as corrosion inhibitors for refined petroleum:

I. Stirring tests-These tests are run on synthetic fluids. The procedure involves the comparison of the amount of iron in solution after a predetermined interval of time of contact of a standardized iron surface with 22 a two-phase corrosive medium with similar determinations in systems containing inhibitors.

Six hundred ml. beakers equipped with stirrers and heaters are charged with 400 ml. of 10% sodium chloride containing p.p.m. acetic acid and 100 ml. of mineral spirits. The liquids are brought to temperature and a l x 1 inch sand blasted coupon is suspended by means of a glass hook approximately midway into the liquid phase of the beaker. The stirrer is adjusted to agitate the liquids at such a rate as to provide good mixing of the two layers.

After 30 minutes, samples of the aqueous phase are taken and the iron content of each sample is determined by measuring the color formed by the addition of hydrochloric acid and potassium thiocyanate in a photoelectric colorimeter.

The protection afiorded by an inhibitor is measured by comparison of the amount of light absorbed by inhibited and uninhibited samples run simultaneously. Percent protection can be determined by the following formula:

where A is the present light absorbed by an uninhibited sample and A is the same value for an inhibited sample. These stirring tests are run at three different temperatures, i.e., room temperature, F. and at F. The compounds shown in Table III, tested in this manner in concentrations of 40 p.p.m., substantially reduce corrosion.

II. Stirring test at high acetic acid concentration-- The above stirring tests are repeated except that the corrosive solution contains 500 p.p.m. of acetic acid instead of 100 p.p.m. The compounds shown in Table III, tested in this manner at concentrations of 100 p.p.m., substantially reduce corrosion.

III. Stirrin test I containing persulfate.ln order to demonstrate the eifectiveness in a very highly corrosive solution stirring test I is repeated except that the corrosive solution also contains 0.2% ammonium persulfate. The compounds shown in Table III, tested in this manner at 1,200 p.p.m., substantially reduce corrosion. I IV. Static rust test.--Weighed coupons are dipped into mineral spirits containing the present composition (100 p.p.m.) for one hour followed by treatment for one week with distilled and synthetic sea Water. The coupons are then cleaned with inhibited 10% HCl, dried and weighed and the weight loss noted. The compound shown in Table III, tested in this manner, substantially reduce corrosion.

V. Tanker tests (cycle tests).This test is described by Malcolrnson et a1. (Annual Meeting of the Society of Naval Architects and Marine Engineers, New York, November 1952). It involves the measurement by weight loss of coupons which have been subjected to the corrosive action of sea water and a hydrocarbon (here gasoline) for a week, followed by contact for one week with sea water and air, and the comparison to the weight loss of coupons subjected to a similar test in which a small amount of inhibitor has been added to the hydrocarbon phase (here gasoline). The compounds shown in Table III, tested at 100 p.p.m., substantially reduce corrosion.

TABLE III Use as Corrosion Inhibitor for Refined Petroleum Test Compound Compound Similarly elfectivecorrosion inhibition is observed with lubricating oil, for example, a turbine oil having the following characteristics:

with various grades of gasoline including those shown in Section 4 of this present application; and jet fuels, for example, those meeting J P1 through JP-6 specifications.

3. ADDITIVES FOR SIJUSI'IING'OILS These new compositions of matter inhibit or prevent the corrosion or rusting of metals when applied thereto in the form of a coating.'

In the shipping and storage of metal articles, particularly ferrous metal articles having machined surfaces, it is highly desirable to protect such articles from the corrosion and rusting which normally occur when metal surfaces are exposed to the atmosphere for any length of time. While such protection should remain efiective over long periods of time under very adverse conditions of humidity, it should likewise be of such nature that it can readily be removed when it is desired to place the metal article into use. Among the various means employed for providing such protection against corrosiomthat of applying a film or coating of a corrosion inhibiting liquid com: position to the metal surface has. enjoyed widest use by reason of its economy and adaptability to all sorts of metal articles ranging from simple pieces to complicated machine assemblies. Such liquid corrosion preventive compositions often comprise a mineral or other non-drying oil base having a corrosion preventive material dispersed or dissolved therein, and are hence usually referred to generically as slushing oils even though in some instances they may not actually contain an oil.

The slushing oils heretofore employed, however, have been subject to numerous disadvantages. In some in-' stances they have been too expensive for widespread general use whereas in others they are too difficult to remove from surfaces to which they have been applied, Many of them have not proved effective over sufiiciently long periods of time, or have not provided the desired degree of protection against corrosion under extreme climatic conditions such as those encountered in the tropics or at sea. V

It has been found that the compositions of this invention are capable of use in inhibiting or preventing the corrosion or rusting of metal surfaces over long periods of time and under adverse climatic conditions.

They can readily be dissolved or dispersed in a suitable liquid vehicle to form inexpensive and highly effective slushing oil compositions. i

While the abovedescribed reactionproducts can, be employed per se in inhibiting or preventing the corrosion or rusting of metals, by reason of their high viscosity they are more readily applied'to metal surfaces in the form of a solution or dispersion in a liquid vehicle. For example, they are dissolved in a relatively light organic solvent, such as hexane, benzene, petroleum ether, carbon tetrachloride, or alight naphtha to form slushing oil compositions of a viscosity suitable for application to metal surfaces by dipping, brushing, or spraying procedures. Such light solvent will evaporate leaving a thin protective coating of the corrosion inhibiting reaction product on the metal surface. When it is desired to use the metal article thus protected, the corrosion preventive coating may readily be removed by washing with a suitable solvent. Gasoline is an excellent solvent for this purpose since it is cheap and universally available The light petroleum distillate known as Stoddard solvent has been found particularly suitable for use as the solvent in preparing liquid protective coating 'compo'sjitio'nscomprising the new corrosion Preventives, and may also be The amount (by weight) of solvent employed will de-' pend upon the nature of the solvent itself as well as upon the thickness of the coating desired on the metal surface, such as from 1 to 99%, for example from 5 to 95%, but preferably 10 to 90%. Ordinarily, however, suitable compositions will contain up to about '90 percent, preferably between about 50 and about 90 precent, by weight of the solvent; When it is desired to apply a thick corrosion preventive coating, the amount of solvent is kept near the minimum, whereas if a thin coating 'ispreferred, the amount'of solvent may be considerably increased. For most application, a composition comprising equal parts of solvent and the corrosion preventive material will be found very satisfactory.

In addition to being employed per se or in the form of the above-described liquid coating compositions, the cor rosion preventive reactionproducts of the present invention may advantageously be employed in conjunction with other corrosion inhibitors, particularly the so-called Alox corrosion reventives manufactured by the Alox Corporation. These latter products are complex mixtures containing hydrocarbons, secondary, and tertiary aliphatic alcohols, aliphatic ketones, keto-alcohols, and high molecular weight saturated aliphatic car-boxylic and hydroxycarboxyl-ic acids. They are obtained by the Burwell process of partially oxidizing petroleum hydrocarbons in the liquid phase at elevated temperatures and pressures as disclosed in US. Patents Nos. 1,690,768 and 1,690,769.

In employing the new corrosion preventive reaction products of the present invention in conjunction wtih such oxidized petroleum hydrocarbon corrosion preventives, the relative proportions of the two products may be varied between wide limits depending upon the degree of corrosion protection desired and the particular products employed.

As with the new corrosion preventive reaction products themselves, the mixtures thereof with the oxidized petroleum hydrocarbon corrosion preventives may be employed per se in applying corrosion preventive coatings to metal surfaces, but are usually more conveniently employed in the form of a solution or dispersion in a suitable liquid vehicle, e.g. Stoddard solvent, benzene, naphtha, etc.

In addition, a variety of other solvents or liquid dispersing media may be employed to prepare a wide variety of corrosion protective compositions whose physical properties are adapted to particular application. Thus, the reaction products herein disclosed may be dissolved or dispersed inheavier oils or the like or even in petrolatum to provide thick liquid or grease-like compositions.

In order to evaluate the present compositions as slushing agents, the following tests are carried out: Y

I. Weighed coupons are coated with the compounds shown in the following table by dipping them into a 10% solution of these compositions in a petrolatum oil. Additional weighed coupons are left uncoated as a control. The coupons are then immersed in distilled and synthetic sea water for a period of one week. Y These coupons are then removed, cleaned by immersion in inhibited 10% HCl, dried and :weighed. The weight loss indicates the protection olfered by the composition.

The compounds shown in Table IV,.tested in this manner substantially diminish corrosion.

The petrolatum oil referred to above is an oil separated in'the deoiling of petrolatum stock used in the preparation of residual microcrystalline wax. Thisoi-l is described in the above.BruceClary article and. is separated by a procedure shown in FIGUREJ of. that article on page 19, under the Residual. Micro Wax flow sheet under Deoiling which follows Flash 400 F. min. Gravity (API) 26/32. Color Dark.

Visc., 210 (saybolt) 80/120. Cold test 70/110.

13.8. & W 1% max.

II. The above procedure is also repeated employing mineral spirits.

The composition shown in Table IV, tested .in this manner substantially diminished corrosion.

TABLE IV Slushing Oil Additives Compound Test Compound 4. MI S CELLANEOU'S ANT I-CO BRO SIVE U SE S In addition, the present compositions are utilizable for numerous purposes. They can be added to a wide variety of vehicles to produce anti-corrosive compositions. They can be dissolved in the vehicle, or they can be dispersed therein in the form of suspension or emulsions.

The vehicles can be liquids or plastics, the basic requirement being that they must be spreadable over metal surfaces. Spreading may be accomplished by immersion, flooding, spraying, brushing, trowelling, etc. It can be oleaginous, i.e., substantially insoluble in Water, or it can be aqueous. Aqueous vehicles include aqueous solutions of liquid, such 'as alcohol-water mixtures and the like. Oleaginous vehicles can be hydrocarbon materials, such as mineral oils and hydrocarbon solvents, or non-hydrocarbon materials, such as fatty oils and fats.

Non-limiting examples of suitable vehicles for the additives of this invention are mineral lubricating oils of all grades; gasolines and other light petroleum products, such as fuel oil; water; alcohols, such as ethanol, isopropanol, butanol, cyclohexanol, methylcyclohexanol, octanol, decanol, dodecanol, hexdeoanol, octadecanol, oleyl alcohol, benzyl alcohol, etc.; phenols; glycols, such as ethylene glycol, propylene glycol, butylene glycol, glycerol, etc.; ketones, such as acetone, methyl ethyl ketone, dipropyl ketone, cyclohexanone, etc.; keto alcohols, such as acetol; others, such as diethyl ether, dipropyl ether, diethylene dioxide, dichloro diethyl ether, diphenyl oxide, diethylene glycol, triethylene glycol, ethylene glycol monobutyl ether, etc.; natural esters, such as ethyl acetate, butyl propionate, cresyl acetate, dodecyl acetate, ethyl maleate, butyl stearate, tridecyl phosphate, tributyl trithiophosphate, triamyl phosphite, etc.; petroleum waxes, such as slack Wax and paraffin Wax; natural waxes, such as carnauba wax, japan wax, beeswax, etc.; natural fats and oils, such as sperm oil, tallow, cottonseed oil, castor oil, linseed oil, tung oil, soy bean oil, oiticica oil, tar oil, oleo oil, etc.; hydrocarbons and halogenated hydrocarbons, such as butanes, chlorinated hexanes, octanes, brominated decanes, dodecanes, Freon, eicosane, benzene, toluene, xylene, cumene, indene, alkyl naphthalenes, etc.;

26 greases; asphalts; chlorinated petroleum fractions, such as chlorowax; and paints, varnishes and the like.

As those skilled in the art will readily appreciate, the applications of the compositions of the present invention are many. Lubricating oils of all types usually permit corrosion of metal surfaces. This poses a problem in the lubricating of all types of engines, particularly steam turbines. Lubricating oils containing the reaction products of this invention are effectively inhibited against such corrosion. Diesel fuels containing these additives will have less tendency to corrode injection nozzles. Steam cylinder oils and cutting oils can be inhibited against corrosive tendencies by the addition thereto of these new additives, particularly the more emulsive types. Greases can be inhibited likewise. Additionally, the more emulsive products of this invention can be substituted in whole or in part for the emulsifying agents commonly used in compounding greases, cutting oils, steam cylinder oils, etc. Hydraulic systems can be protected against corrosion by using hydraulic fluids containing the additives of the present invention.

The storage of infrequently used machinery, and the shipment and storage of metal shapes and metal parts, such as machined sewing machine parts or gun parts, present corrosion problems. Such corrosion can be prevented by treating them with slushing oils containing the additives of this invention, by coating them with organic solvent solutions or dispersions of these additives, such as the benzene solutions described hereinbefore, or by treating the surfaces thereof with dispersions of these additives in water. Corrosive tendencies of coolants and antifreeze solutions or mixtures, such as those used as coolants in internal combustion engines, can be reduced by addition thereto of the reaction products of this invention. Such antifreezes include water, alcohol-water, glycols, glycol-water, etc. When gasoline and other fuels are stored in drums or tanks, water often enters the storage space, as by breathing, and corrodes the inner surfaces thereof. This can be prevented through the use of the additives contemplated herein.

Relatively more permanent corrosion-preventive coatings can be produced by the application to metal surfaces of paints, and the like, containing the additives of this invention. Vehicles utilizable for this purpose are paints, varnishes, lacquers, drying oils, asphalt roofing compositions, and the like.

The amount of the reaction products which are added to a vehicle to produce a composition in accordance with this invention varies between about 0.001 percent and about 50 percent or more by weight, depending on the specific use contemplated and on the specific reaction products selected. Generally, it is suflicient to use an amount varying between 0.01 percent and about 10 percent. However, smaller amounts, as low as about 0.001 percent, will be effective in some cases. Likewise. amounts up to as much as about 50 percent or more are required when the vehicle contains resinous bodies, or when the reaction product is also used as an emulsifier, such as in a steam cylinder oil.

Other substances in addition to the reaction products of this invention can be added to the compositions contemplated herein to impart other desirable properties thereto. For example, there may be added antioxidants, pour point depressants, V.I. improvers, antidetonants, cetane number improvers, emulsifiers, thinners, driers, etc.

5. USE AS LEAD SCAVENGERS AND ANTI-FOULING AGENTS This phase of the present invention relates to an improved leaded gasoline for an internal combustion engine employing an electric spark for igniting the combustible fuel mixture and to an improved method of operating such.

The use of lead compounds in gasolines to increase the octane ratings thereof is extremely widespread. There are, however, several rather serious adverseelfects which acompany the use of leaded gasolines. One of these effects, the deposition of various lead compounds within the combustion chambers of the engines, has been at least partially remedied by the use of halohydrocarbon scavengers such as ethylene dibromide. Another adverse effect, which has been attributed to the lead anti-knock compounds, is mis-firing of the engine due to spark plug fouling. This spark plug fouling is quite prevalent under conditions of high temperature engine operation and, particularly in the case of aircraft engines, is a very serious type of trouble.

It has been now found that the use, as a lead scavenger in leaded gasoline fuel compositions, of a mixture of a halohydrocarbon scavenger and of a smaller amount of the present ester-amide-acid compounds will result in greatly improved operation of spark ignition internal combustion engines. More particularly, the use of such scavenger compositions substantially eliminates spark plug fouling, or at least minimizes such fouling to a point where it is no longer a material consideration in engine operation. This outstanding advantage is obtained without having the anti-knock characteristics of the fuel deleteriously affected by the presence of the scavenger compositions.

The ester-amide-acid. compounds inthe present scavenger compositions will be referred to hereinafter as antifouling compounds. The halohydrocarbon will be referred to as halohydrocarbon scavenger compounds or halogen scavenger compounds.

The halohydrocarbon scavenger which makes up the major proportion of the scavenger compositions of the present invention may be, for example, any of the numerous halogen scavenger compounds already known, such as ethylene dibromide and ethylene dichloride (U.S. 2,398,281), acetylene tetrabrornide (U.S. 2,490,606), hexachloropropylene, monobutanes and pentanes (U.S. 2,479,900 and U.S. 2,479,- 902), polyhalo alkyl benzenes (U.S. 2,479,901 and U.S. 2,479,903), and the like, having a volatility between about 100 and about 0.1 mm. Hg at 50 C.

The amount of halogen scavenger and anti-fouling compound present in the lead gasoline will be expressed as follows: 1 e

(1) Gram-moles of halogen scavenger divided by the number of halogen atoms present in the molecule (hereafter also called halogen-gram-mole').

(2) Gram-moles of anti-fouling compound.

(3 Gram-moles of lead present in the gasoline.

When using the scavenger compositions in this phase of the present invention, the total amount or sum of halogen-gram-moles of the halogen scavenger plus the gram-moles of anti-fouling agent present will generally fall between about 1.8 and about 3 per gram moles of the lead content of the gasoline, but may advantageously a more closelyspecifiedboiling range, generally running and polyhalo propanes,

present is too large, excessive wear and corrosion of cer- V tain operating parts, such as exhaust valvesand valve guides, is noted. If too small a quantity of halogen scavenger is used, the lead deposits are not efiectively scavenged. If too small a quantity of the anti-fouling compound is used, the sparkplug fouling will not be materially reduced; and if too much of that compound is present the amounts of deposits and the plug' fouling are both increased. In general the gram-mole ratio of the halogen scavenger or scavengers. to the anti-fouling agents should be between about 3:2 and about 100:1

much greater than that required for motor fuels.

so that the anti-fouling compound is present in an amount of between about 0.01 and about 1.0 gram mole or more, and preferably between about 0.05 and about 0.5 gram mole per gram moleof lead. It is preferred that the Weight concentration of the anti-fouling additive in the fuel be kept below 0.1%. It is to be under stood that more than one of the compounds from each class (i.e., halogen scavenger or anti-fouling agent), may be used in any single composition, just so the total quantity of each type falls within the limits set forth above.

While it is to be'understood that the present compositions may be utilized in any leaded gasoline fuel, the compositions are of particular importance with respect to use in the reciprocating internal combustion engine gasoline fuels, and especially such aviation fuels. This is true because of the relatively more frequent occurrence of spark plug fouling in aviation engines, with the greater inherent danger to human life in the case of failures of such engines. In addition to the lead antidetonant and the scavenger composition, the gasoline fuels, or the concentrates for addition thereto may also contain additional. corrosion inhibitors and stabilizers, such as 2,4-dimethyl-6-tertiary butyl-phenol and other alkyl phenols, N,NGdibutyl-p-phenylene diarnine hydroquinone, phenyl-alpha, naphthylamine, N-butyl-p-aminophenol, alpha-naphthol, etc., dyes and the like.

By the term leaded gasoline, and the terms of similar import, is meant a petroleum fraction boiling in the gasoline hydrocarbon range (between about 50 F. and about 450 F.) to'which has been added a small amount, usually between about 1 and about 6 cc. per gallon, of a metalldorganic, usually an organo-lead, anti-knock compound, such as tetra-alkyl lead, e.g., tetra-ethyl lead, tetra-isopropyl lead, etc.

V The fuels to which the present scavenger compositions are added are preferably those which are relatively stable withrespeot to oxidation or gum formation. The stability may result from the use of stable base stocks such as aviation ,alkylate, straight run gasoline fractions, or other fractions which have been highly refinedto remove olefins, or the stability may result from the use of oxidation stabilizers, such as those mentioned above.

As indicated above, the scavenger compositions of this invention are particularly'useful in aviation gasoline. By the term faviation gasoline is meanta relatively high grade of gasoline fuel used in aviation engines, as distinguished from the lower quality gasolines, or motor fuels used in automotive engines. Aviation fuels have from a minimum of about 100 F. to a maximum of about 350 F. The octane number of such fuels is generally in excess of 100. Because of the demand for high quality, thermally cracked fractions arenever used in aviation gasolines. Catalytically cracked fractions may sometimes be used, but' only after treatment to remove olfins. One. of'the reasons for the restrictions upon incorporation of cracked gasolines in aviation fuels is that: the oxidation stability of aviation fuels must be For example, when tested according to a'method such as 'describ'cd in the patent issued to Thomas. W. Bartram, "U.S. 2,256,187, an aviation fuel base stock will go well beyond 4 or 5 hours before the oxygen pressure will have decreased :by 5 pounds per square inch. The following examples are presented to illustrate this phase of the present invention. Tests are run using the single'cylinder test procedures which deposits are accumulated'for a period of 40 hours under cyclic conditions representative of different operating conditions of a motor car. The base fuel is composed of catalytically cracked stockand'10%' of motor alkylate witl1 3.0 ml. of tetraethylxlead per gallon. It is representative of commercial premium grade gasoline for automobile use. In each case, the amount ofdeposit recorded in the build- 29 up deposits on the valves, spark plugs fouling, and the like is significantly less than the control which contained no ester-amide-acid compound.

The following mixtures are tested with the above gasoline:

TABLE V Scavenger Anti-fouling agent Test Compound Compound Weight] Weight! gal. gal.

Ethylene dibromide ethylene dichloride.

cnenvrcnor o Ethylene dibrornide..- .do

do Acetylene tetrabromid The above compositions are also similarly effective in aviation grade gasolines are exemplified by a 115/ 130 grade aviation gasoline containing 4.6 ml. of tetraethyl lead.

From the above description it is evident that this phase of the present invention relates to a blend of gasoline of appropriate boiling range and octane number, a suitable lead compound such as rtetraethyl lead in the usual range of amounts, a halohydrocarbon such as ethylene dibromide in the usual range of amounts, and a minor amount of the ester-amide-acid of the present invention, with or without other additives.

The utility of the invention is that such an engine, which supplied with the described fuel in admixture with air for combustion, sufiers fewer deposit-induced or surface" ignitions and produces less spark plug fouling than when operated with the same fuel without the ester-amideacid compound. The engine thus delivers more power, because of the reduced loss from abnormal combustion. Compared with known fuel blends having additives to attain this same objective, my fuel requires a smaller weight of additive to achieve an acceptable reduction of abnormal combustion and, further, by causing little if any deposits in the combustion space, it minimizes the increase in the octane requirement of the engine caused by the deposits.

In addition to its function as an anti-fouling agent the ester-amide-aci-d composition also acts as corrosion inhibitors which permit a reduction in the amount of corrosion inhibitor required or their complete elimination, with obvious economic advantage. The anti-corrosive effectiveness of these ester-amide-acid compounds has been described above.

Having thus described my invention, what I claim as new and desire to obtain by Letters Patent is:

1. A compound having the formula wherein Z is a member selected from the group consisting of an alkylene radical having at least three carbon atoms and an aryl substituted alkylene radical; wherein one of each of the R and R on each succinic moiety is an alkenyl radical having at least two carbons and the other R and R are hydrogen; and wherein Y is a member selected from the group consisting of hydrogen and a hydrocarbon group having 1-18 carbon atoms.

3 0 2. The compound of claim 1 wherein Z is CHa-C|H- Y is hydrogen; one of each of the R and R is an alkenyl group containing 12 carbons, and the other R and R are hydrogen.

3. The compound of claim 1 wherein Z is Y is hydrogen; one of each R and R is an alkenyl group containing 12 carbons and the other R and R are hydrogen.

4. The compound of claim 1 wherein Z is "1 is hydrogen; one of each R and R is an alkenyl group containing 12 carbons and the other R and R are hydrogen.

5. The compound of claim 1 wherein Z is CHrCH- Y is hydrogen; one of each of the R and R is an alkenyl group containing 12 carbons and the other R and R are hydrogen.

6. The compound of claim 1 wherein Z is -CH1CH Y is an alkyl group; one of each of the R and R is an alkenyl group containing 12 carbons and the other R and R are hydrogen.

7. A compound of the formula where Z is a member selected from the group consisting of an alkylene group having 3-l2 carbon atoms and an aryl substituted alkylene radical and one each of R and R is an alkenyl group having 3-32 carbon atoms, the other R and R being hydrogen; and Y is selected from the group consisting of hydrogen and lower alkyl.

8. The compound of claim 7 where one each of R and R is an alkenyl group having 8-l8 carbon atoms, the other R and R being hydrogen; Y is hydrogen.

9. The compound of claim 7 where Z is an alkylene group having 3-8 carbon atoms and one each of R and R is an alkenyl group having 8-48 carbon atoms, the other R and R being hydrogen, and Y is hydrogen.

10. The compound of claim 9 where Z is on; -OH JH and Y is hydrogen.

11. The compound of claim 9 where Z is ---(CH;);,- and Y is hydrogen.

12. The compound of claim 9 where Z is and Y is hydrogen.

31 13. The compound of claim 9' where Z is and Y is hydrogen.

14. The compound of claim 9 Where Z is CH2 CH- and Y is a lower alkyl group.

References Cited in the file of this patent UNITED STATES PATENTS Verdol July 5, 19'60' 

7. A COMPOUND OF THE FORMULA 